1 /* PSPP - a program for statistical analysis.
2 Copyright (C) 2004, 2009 Free Software Foundation, Inc.
4 This program is free software: you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation, either version 3 of the License, or
7 (at your option) any later version.
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
14 You should have received a copy of the GNU General Public License
15 along with this program. If not, see <http://www.gnu.org/licenses/>. */
22 #include <gsl/gsl_histogram.h>
23 #include <gsl/gsl_randist.h>
26 #include <output/charts/plot-hist.h>
27 #include <output/charts/plot-chart.h>
28 #include <output/chart-provider.h>
30 #include <data/variable.h>
31 #include <libpspp/cast.h>
32 #include <libpspp/hash.h>
33 #include <output/chart.h>
34 #include <math/histogram.h>
35 #include <math/moments.h>
38 #define _(msgid) gettext (msgid)
40 static const struct chart_class histogram_chart_class;
42 /* Write the legend of the chart */
44 histogram_write_legend (cairo_t *cr, const struct chart_geometry *geom,
45 double n, double mean, double stddev)
47 double y = geom->data_bottom;
52 char *buf = xasprintf ("N = %.2f", n);
53 cairo_move_to (cr, geom->legend_left, y);
54 chart_label (cr, 'l', 'b', geom->font_size, buf);
55 y += geom->font_size * 1.5;
61 char *buf = xasprintf ("Mean = %.1f", mean);
62 cairo_move_to (cr,geom->legend_left, y);
63 chart_label (cr, 'l', 'b', geom->font_size, buf);
64 y += geom->font_size * 1.5;
70 char *buf = xasprintf ("Std. Dev = %.2f", stddev);
71 cairo_move_to (cr, geom->legend_left, y);
72 chart_label (cr, 'l', 'b', geom->font_size, buf);
80 hist_draw_bar (cairo_t *cr, const struct chart_geometry *geom,
81 const gsl_histogram *h, int bar)
87 const size_t bins = gsl_histogram_bins (h);
88 const double x_pos = (geom->data_right - geom->data_left) * bar / (double) bins ;
89 const double width = (geom->data_right - geom->data_left) / (double) bins ;
91 assert ( 0 == gsl_histogram_get_range (h, bar, &lower, &upper));
93 assert ( upper >= lower);
95 height = gsl_histogram_get (h, bar) *
96 (geom->data_top - geom->data_bottom) / gsl_histogram_max_val (h);
98 cairo_rectangle (cr, geom->data_left + x_pos, geom->data_bottom,
101 cairo_set_source_rgb (cr,
102 geom->fill_colour.red / 255.0,
103 geom->fill_colour.green / 255.0,
104 geom->fill_colour.blue / 255.0);
105 cairo_fill_preserve (cr);
109 draw_tick (cr, geom, TICK_ABSCISSA,
110 x_pos + width / 2.0, "%g", (upper + lower) / 2.0);
113 struct histogram_chart
116 gsl_histogram *gsl_hist;
124 /* Plots a histogram of the data in HIST with the given LABEL.
125 Labels the histogram with each of N, MEAN, and STDDEV that is
126 not SYSMIS. If all three are not SYSMIS and SHOW_NORMAL is
127 true, also draws a normal curve on the histogram. */
129 histogram_chart_create (const struct histogram *hist, const char *label,
130 double n, double mean, double stddev,
133 struct histogram_chart *h;
135 h = xmalloc (sizeof *h);
136 chart_init (&h->chart, &histogram_chart_class);
137 h->gsl_hist = hist->gsl_hist ? gsl_histogram_clone (hist->gsl_hist) : NULL;
138 h->label = xstrdup (label);
142 h->show_normal = show_normal;
147 histogram_chart_draw (const struct chart *chart, cairo_t *cr,
148 struct chart_geometry *geom)
150 struct histogram_chart *h = UP_CAST (chart, struct histogram_chart, chart);
154 chart_write_title (cr, geom, _("HISTOGRAM"));
156 chart_write_ylabel (cr, geom, _("Frequency"));
157 chart_write_xlabel (cr, geom, h->label);
159 if (h->gsl_hist == NULL)
161 /* Probably all values are SYSMIS. */
165 bins = gsl_histogram_bins (h->gsl_hist);
167 chart_write_yscale (cr, geom, 0, gsl_histogram_max_val (h->gsl_hist), 5);
169 for (i = 0; i < bins; i++)
170 hist_draw_bar (cr, geom, h->gsl_hist, i);
172 histogram_write_legend (cr, geom, h->n, h->mean, h->stddev);
175 && h->n != SYSMIS && h->mean != SYSMIS && h->stddev != SYSMIS)
177 /* Draw the normal curve */
179 double x_min, x_max, not_used;
180 double abscissa_scale;
181 double ordinate_scale;
184 gsl_histogram_get_range (h->gsl_hist, 0, &x_min, ¬_used);
185 range = not_used - x_min;
186 gsl_histogram_get_range (h->gsl_hist, bins - 1, ¬_used, &x_max);
188 abscissa_scale = (geom->data_right - geom->data_left) / (x_max - x_min);
189 ordinate_scale = (geom->data_top - geom->data_bottom) /
190 gsl_histogram_max_val (h->gsl_hist);
192 cairo_move_to (cr, geom->data_left, geom->data_bottom);
193 for (d = geom->data_left;
194 d <= geom->data_right;
195 d += (geom->data_right - geom->data_left) / 100.0)
197 const double x = (d - geom->data_left) / abscissa_scale + x_min;
198 const double y = h->n * range *
199 gsl_ran_gaussian_pdf (x - h->mean, h->stddev);
201 cairo_line_to (cr, d, geom->data_bottom + y * ordinate_scale);
210 histogram_chart_destroy (struct chart *chart)
212 struct histogram_chart *h = UP_CAST (chart, struct histogram_chart, chart);
213 if (h->gsl_hist != NULL)
214 gsl_histogram_free (h->gsl_hist);
219 static const struct chart_class histogram_chart_class =
221 histogram_chart_draw,
222 histogram_chart_destroy